Problems with soldering

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As has been said, no it isn't for general small electronics 25 - 30 watt is ideal
If you have the experience then 30W is acceptable, but for beginners that (paired with some cheap iron) often brings an uphill battle.
Especially if the temperature is set at some fixed point (usually somewhere above 400C). The stable, adjustable temperature almost as important I think as the available power. Beginners are easier to catch up to task if they can get a bit higher temperature than the necessary - but still without oxidizing the solder in moments.

I don't think so.
Your Weller won't work any more seriously than 20W average.
 
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If you have the experience then 30W is acceptable, but for beginners that (paired with some cheap iron) often brings an uphill battle.
Especially if the temperature is set at some fixed point (usually somewhere above 400C). The stable, adjustable temperature almost as important I think as the available power. Beginners are easier to catch up to task if they can get a bit higher temperature than the necessary - but still without oxidizing the solder in moments.


Your Weller won't work any more seriously than 20W average.
From my years of experience in soldering, high temp and powerful iron is the KEY for good soldering(with good technique). Even with SMD as small as 0402, I use 800deg tips all the way and use the biggest tip possible for the job so the extra mass will help keeping the temperature. Nothing is worst than it takes a few seconds or more to even melt the solder. A small and low temperature iron requires heating stuff for a long time to bring it to melt the solder, the flux will all be burnt away and create cold solder joint. People need to learn and practice to do soldering fast. If I have to heat things for a few seconds to melt solder, I always touch up and refloat with new solder to make sure the solder joint looks shinny to ensure it's a good solder. You keep heating and heating using a small iron, the solder joint will likely look dull, that's the tell tale sign of cold solder that will present problem in the future.

Keeping stable temperature and recovery is very important. My suspicion why my Aoyue is so bad is because even if I set to higher temperature of 450deg , the moment the tip touch the wire or other things, the temperature drops and recovery is very slow. The result is it won't melt the solder. It uses a ceramic rod heating element placing inside the hollow cavity of the solder tip, I bet the heat transfer is bad. Once the tip touch any surface, temperature drops and it's too slow to transfer heat from the ceramic rod to the tip to bring the temperature back to spec.

Soldering is NOT as easy as it looks, takes practice and practice. I taught technicians how to solder, you'll be surprised how many people that work in the field don't know how to solder. Particular now a days soldering SMD parts, it's a skill to solder. With good technique, one can solder SMD much faster than through hole components. I use a lot of SMD in my design at home, I try not to use through hole parts if I can help it. Reworking on SMD pcb is a lot easier than through holes.

As for my Weller WTCPT, it's spec for 60W, I don't know what is the average. It's a strong iron for pcb work. Heat recovery is much better than the Aoyue that is 70W. What is the average power of the 25W soldering iron?
 
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I use 800deg tips all the way
Then at the company I'm working you would not be allowed to use the equipment at all and most likely you would get yourself fired in the middle of the probation period.

Overheating the PCB/components is one of the biggest taboos, especially in SMD soldering. If you can't do the job at acceptable temperatures you better get a hot plate.
 
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Then at the company I'm working you would not be allowed to use the equipment at all and most likely you would get yourself fired in the middle of the probation period.

Overheating the PCB/components is one of the biggest taboos, especially in SMD soldering. If you can't do the job at acceptable temperatures you better get a hot plate.
What company are you working for? I worked for more than 30 years as a technician, an engineer and manager of engineer in quite a few companies, never have any issue.

It's the technique and the speed. I never ever have problem with SMD parts. I am still building a lot of boards for my amplifiers with a lot of SMD parts, never have a problem peeling traces. Actually if you have a weak iron and has to stay on the pcb for a long time, you rip traces and pads out.

As a manager, I would fire someone that keep giving me boards with cold solder joints.
 

tech99

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I am wondering if the wire you are trying to solder is enamelled? Goes it have an insulating varnish? Try scraping the surface with a knife.
 
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What company are you working for?
Strict. We are developing and testing/reworking our own boards for our own industrial equipment. While scrapped components are somewhat acceptable, scrapped PCBs are painful since that means scrapping a bunch of other component and cost too. Actually I was the one who finally managed to establish some decent soldering culture here, and since that there are barely any boards got wrecked and product quality shoot up.

In short, the starting point was: 350-360C is preferred, but anything above 380C is forbidden: if you still can't finish the job in seconds, then ask. Anything with not rosin based flux is forbidden.

Not too complicated but surprisingly successful in guiding the new guys, should they be technicians or fresh engineers.
 
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Even I was and engineer and Manager of EE, I did a lot of work building boards at crunch time as I was faster than the technicians. I am doing more soldering and building boards since I retired as I don't have people to boss around, I am the designer and assembler and all at home. I was contracting at home for over a year and half working at home so I have to build all the boards of my designs using TSSOP and 0402 parts.

I am retired, but I am very active in designing high end audiophile power amps that mixed power electronics components with SMD on one board. Attached are what I am working on, I spent like 3 hours a day building and testing stuffs. I build in higher quantity for comparisons. You can see those

1)IPS boards are all SMD with a few through parts.

2) Old power amp boards L that I am at the process of pulling out parts to reuse. It's mixed SMD and large transistors on one board. What make it very difficult for soldering is I have to use 2oz copper for high current purpose. Try soldering SMD parts on 2oz copper.

3) Scrapted boards are boards in various stages of pulling out parts. Those transistors, capacitors and a lot of stuffs are expensive. I even recycle SMD parts.

4) Boards to recycle are piles of boards either obsoleted or parts been pulled and ready to go to recycle.

I do a lot of soldering and rework now that I am retired and no one to boss around and dump the dirty work on anymore like when I was at work. It's all on me. Particular I fab boards in China as it's a lot cheaper. There quality is much lower, they don't hold up to soldering heat anywhere close to the boards made in USA. This make it so much more critical in soldering. I have absolutely no problem using what I described.

I don't want to debate this any more, to each their own, we just agree to disagree. I walked the mile.......many miles on this, it works for me and serve me well.
 

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davenn

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I am wondering if the wire you are trying to solder is enamelled? Goes it have an insulating varnish? Try scraping the surface with a knife.
.

Yeah, I commented about that some posts back 😉

the OP hasn't responded
It seems the OP @Wrichik Basu has gone AWOL
 

Wrichik Basu

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would like to see a photo of the wire ends you were trying to solder
.

Yeah, I commented about that some posts back 😉

the OP hasn't responded
It seems the OP @Wrichik Basu has gone AWOL
Yeah yeah, sorry for the delayed reply. I was busy in some college work...

Here is a photo of the type of wires that I generally use. This one is the thickest one available locally.

20191021_120729.jpg
 
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Wrichik Basu

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Some months back, I found a diode bridge that I had made when I was young (idea was to convert 220V AC to 220V DC). I was laughing at my own stupid ideas, but then decided to test my soldering "skills" on that. The wires were a bit tarnished, but they were too twisted for me to rub them with a sand paper. I kind of dipped the joints into flux. The result was this:

20191021_120941.jpg


This was perhaps expected. A good and smooth solder requires a good joint first. The joints, in this case, were wires twisted together in almost any fashion. I can't even think of such joints nowadays.
 
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The wires were a bit tarnished, but they were too twisted for me to rub them with a sand paper. I kind of dipped the joints into flux. The result was this:
It is hard to 'repair' a tarnished wire. I suggest to give up on them at the start: most of the time it is just better to cut it shorter and strip it again.
This 'result' won't give a good example. I can tell that the soldering iron is burning hot (the insulation of the wire on the top got burned), the flux is burnt as well - but for a tarnished wire (and oxidized component legs) it is not really about your skill.

Try to tin the wire on the photo in #34 and post a picture of that.

 

Wrichik Basu

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Try to tin the wire on the photo in #34 and post a picture of that.
I tried to tin that one, but it was too thick for my 25W soldering iron to handle. So I picked up a thinner wire of the same quality. After trying a few times, this is the best I got today:

20191024_153230.jpg 20191024_153833.jpg 20191024_153920.jpg

I won't say that it is good when compared to something done by a professional. There is some cold solder near the bottom, which I couldn't prevent even after putting flux paste. Perhaps more practice is needed on my side.

In addition, here is a better picture of the tip of the soldering iron (the pictures posted previously in this thread were perhaps of not a good quality):

20191024_153702.jpg
 
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After trying a few times, this is the best I got today:
As long it is just an occasional soldering what does not matter much (low voltage, low current, no responsibility), then it is passable.
However: the insulation is still damaged, long up from the stripped part: the surface is uneven, the flux is burnt brown. Won't pass anywhere where it really matters.
I don't think this will be much better later on. To heat up the wire at 25W you really need the high temperature, but with a high temperature iron it is really difficult to spare the insulation and the flux.

Link the process on a 4mm2 wire with an old and battered Weller WSP-80 80W soldering iron @360°C (!).
Still not perfect, but the flux kept fresh (yellow), the surface is nice shinny and the insulation is intact.
Could have been faster but the magnifying glass was in the way.
I still suggest to get a better soldering iron.
 

Wrichik Basu

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I still suggest to get a better soldering iron.
Yeah absolutely, I know that I won't be able to go far with this 25W. I will be buying a better one next month or so.

In your video, the wire brilliantly absorbs the solder. In my case, the solder doesn't melt unless I touch it near the tip of the iron. Temperature issue, of course.

By the way, I tried using this iron on a faulty pcb that I had. It could desolder the joints, and re-solder them as well (except the joints of the IC). Maybe those joints required lower temperature, so this iron could do it.
 
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